A Robust Composite Control Method for LCL Grid-connected Inverter Based on SiC MOSFETs under Weak Grid

An improved control strategy for three-phase grid-connected inverters with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d-and q-axes grid currents is interacted in the traditional control method, and the waveform quality of the grid current is poor. As the reference output voltage cannot directly reflect the change of the reference grid current with the traditional control strategy, the dynamic response of the grid-connected inverter is slow. In order to solve the aforementioned problems, the d-and q-axes grid currents in the decoupled components of the grid current controller are substituted by the d-and q-axes reference grid currents, respectively. The operating principles of the traditional and proposed control methods are illustrated. Experimental results show that the grid-connected inverter with the improved control strategy has high waveform quality of the grid current and fast dynamic response.

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Modeling and Resonance Damping for the CM Loop of the MLCL-Filtered Grid-Connected Inverter with Variable Inductors Under the Weak Grid Condition

IEEE Journal of Emerging and Selected Topics in Power Electronics ◽

10.1109/jestpe.2021.3050791 ◽

2021 ◽

pp. 1-1

Author(s):

Jiansong Zhang ◽

Xu Yang ◽

Wenjie Chen ◽

Hongwei Zhou

Keyword(s):

Weak Grid ◽

Resonance Damping ◽

Grid Connected Inverter

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Single-phase Photovoltaic Grid-connected Inverter Current Control Method Based on MRAC

Proceedings of the 2018 7th International Conference on Energy, Environment and Sustainable Development (ICEESD 2018) ◽

10.2991/iceesd-18.2018.38 ◽

2018 ◽

Author(s):

Ruiping Zhang ◽

Hongxia Lu ◽

Jie Yang ◽

Tingrong Zhang

Keyword(s):

Single Phase ◽

Control Method ◽

Current Control ◽

Grid Connected Inverter

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Impedance Shaping of LCL-Type Grid-Connected Inverter to Improve Its Adaptability to Weak Grid

CPSS Power Electronics Series - Control Techniques for LCL-Type Grid-Connected Inverters ◽

10.1007/978-981-10-4277-5_10 ◽

2017 ◽

pp. 227-248

Author(s):

Xinbo Ruan ◽

Xuehua Wang ◽

Donghua Pan ◽

Dongsheng Yang ◽

Weiwei Li ◽

...

Keyword(s):

Weak Grid ◽

Grid Connected Inverter

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Composite Control Strategy of Output Current of LCL Photovoltaic Grid-Connected Inverter

Journal of Physics Conference Series ◽

10.1088/1742-6596/2136/1/012015 ◽

2021 ◽

Vol 2136 (1) ◽

pp. 012015

Author(s):

Shengqing Li ◽

Xinluo Li ◽

Qiang Wu ◽

Xiafei Long

Keyword(s):

Control Strategy ◽

Block Diagram ◽

Harmonic Distortion ◽

Harmonic Suppression ◽

Output Current ◽

Control Block ◽

Current Harmonics ◽

Suppression Effect ◽

Composite Control ◽

Grid Connected Inverter

Abstract In order to further optimize the output current harmonic suppression effect of photovoltaic grid-connected inverters, a composite control strategy of LCL type photovoltaic grid-connected inverter output current is proposed. This strategy combines proportional complex integral (PCI) control and repetitive control (RC) in parallel, draws a composite control block diagram, introduces a transfer function, and designs PCI and RC control parameters. Prove that the compound control can reduce current harmonics, achieved the purpose of reducing the steady-state error of the fundamental frequency. And adopts a new PCI composite control strategy, which helps to save the cost of the control system. By building the MATLAB/Simulink simulation platform and establishing the PCI+RC composite control model of LCL photovoltaic grid-connected inverter, the comparison of the simulation results shows that compared with the PI+RC control strategy, the total harmonic distortion rate of the grid-connected current is reduced by 25.77. %, significantly improving the quality of grid-connected current.

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